NEET 2016 Phase 2 · PhysicsCircular radiusPrevious Year Question
An electron is moving in a circular path under the influence of a transverse magnetic field of 3.57 × 10⁻² T. If the value of e/m is 1.76 × 10¹¹ C/kg, the frequency of revolution of the electron is:
Answer: (A) 1 GHz. Answer: (A) Solution: Cyclotron frequency f = qB/(2πm) = (e/m)·B/(2π).
- A.1 GHz✓
- B.100 MHz
- C.62.8 MHz
- D.6.28 MHz
Correct Answer
(A) 1 GHz
Solution & Explanation
Answer: (A) Solution: Cyclotron frequency f = qB/(2πm) = (e/m)·B/(2π). f = (1.76 × 10¹¹ × 3.57 × 10⁻²)/(2 × 3.14) f ≈ (6.28 × 10⁹)/6.28 ≈ 1 × 10⁹ Hz = 1 GHz. → option A.
🎯
43,000+ questions in हिंदी & English · one-tap toggle
Open →📚Practice all NEET Physics PYQs chapter-wise →💡Don't get it? Learn the Moving Charges And Magnetism concepts →Practice NEET 2016 Phase 2 Physics — free, with instant solutions
43,000+ NEET questions solved step-by-step, chapter-wise, in the MedicNEET app.
More NEET PYQ solutions
PhysAn electron (mass 9 × 10⁻³¹ kg and charge 1.6 × 10⁻¹⁹ C) moving with speed c/100 (c = speed of light) is injected into a magnetic field B of magnitude 9 × 10⁻⁴ T perpendicular to its direction of motion. We wish to apply a uniform electric field E together with the magnetic field so that the electron does not deflect from its path. Then (speed of light c = 3 × 10⁸ m s⁻¹)PhysIonized hydrogen atoms and α-particles with same momenta enter perpendicular to a constant magnetic field B. The ratio of the radii of their paths rₕ : r_α will be:PhysAn electric dipole with dipole moment 5 × 10⁻⁶ C·m is aligned with the direction of a uniform electric field of magnitude 4 × 10⁵ N/C. The dipole is then rotated through an angle of 60° with respect to the electric field. The change in the potential energy of the dipole is:PhysTwo identical charged conducting spheres A and B have their centres separated by a certain distance. Charge on each sphere is q and the force of repulsion between them is F. A third identical uncharged conducting sphere is brought in contact with sphere A first and then with B and finally removed from both. New force of repulsion between spheres A and B (radii negligible vs separation, treated as point charges) is best given as:PhysThe plates of a parallel plate capacitor are separated by d. Two slabs of different dielectric constant K1 and K2 with thickness 3d/8 and d/2 respectively are inserted in the capacitor. Due to this, the capacitance becomes two times larger than when there is nothing between the plates. If K1/K2 = 1.25, the value of K1 is:PhysA sphere of radius R is carved out of a uniform solid sphere of radius 2R (internally tangent, so its centre is at distance R from the big centre). The ratio of the moment of inertia of the small sphere to that of the remaining part, both about the Y-axis through the big sphere's centre, is:PhysThe Sun rotates once in 27 days. If it expanded to twice its present radius (uniform-density sphere, no external influence), its new period would be about:PhysA uniform rod of mass 20 kg and length 5 m leans against a smooth vertical wall, making 60° with the wall; its lower end rests on a rough horizontal floor. The friction force exerted by the floor is: (g = 10 m/s²)